Metallic-covalent interatomic potential for carbon in iron
Metallic-covalent interatomic potential for carbon in iron
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DOI：
10.1103/physrevb.78.165115
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发表时间：
2008-10-01
影响因子：
3.7
通讯作者：
Ackland, Graeme J.
中科院分区：
文献类型：
--
作者：
Hepburn, Derek J.;Ackland, Graeme J.
现有的铁-碳系统的原子间相互作用势在描述甚至最简单的缺陷时都存在定性缺陷。与更精确的第一原理计算相反，所有先前的电势显示碳与过配位缺陷的强键合（例如，自激，位错核心）和未能准确地再现碳空位复合物的能量学。因此，将它们应用于分子动力学中更复杂环境的结果是不可靠的。这个问题源于势能设计中的一个基本错误未能描述碳p电子的短程共价键。我们描述了一个解决方案的问题，并提出了一个经验潜力的基础上的见解，从密度泛函理论，显示共价型键的碳。电位正确地描述了碳和铁在各种缺陷环境中的相互作用。它具有嵌入原子方法的形式，因此适合于十亿原子的分子动力学模拟。
Existing interatomic potentials for the iron-carbon system suffer from qualitative flaws in describing even the simplest of defects. In contrast to more accurate first-principles calculations, all previous potentials show strong bonding of carbon to overcoordinated defects (e.g., self-interstitials, dislocation cores) and a failure to accurately reproduce the energetics of carbon-vacancy complexes. Thus any results from their application in molecular dynamics to more complex environments are unreliable. The problem arises from a fundamental error in potential design-the failure to describe short-ranged covalent bonding of the carbon p electrons. We describe a resolution to the problem and present an empirical potential based on insights from density-functional theory, showing covalent-type bonding for carbon. The potential correctly describes the interaction of carbon and iron across a wide range of defect environments. It has the embedded atom method form and hence appropriate for billion atom molecular-dynamics simulations.